There is no built in functionality in Away3D 3.6 that I know of to do what you want in a direct way. I would recommend that you analyze your needs using the *Method of Separating Axis*. You could first discard containment comparing the position of the point with the bounding sphere of the mesh, if that does not fail you could use the method to check if the point is within the bounding cube of the mesh. If that does not fail you could further use the method by checking if the point is on the outer side of any of the mesh's faces. The idea is to discard the possibility of the point being inside the mesh, instead of directly detecting if it is. Check out the method.
Btw, we are moving support to www.away3d.com/forum I recommend that you go there for further inquires. hth, li